Posts Tagged ‘gut bacteria’

We’re learning what a vital role good gut bacteria play in immune health, brain health, mood, and, of course, gut health. We also know that the best way to beef up your good gut bacteria is through eating lots of different kinds of vegetables and fruits every day. But researchers have discovered yet another way to promote healthy gut bacteria: Regular exercise.

Our digestive tract is home to trillions of gut bacteria that weigh about three to four pounds all together, and are made up of over a 1,000 different species and 5,000 strains. Our body depends on these gut bacteria to:

Metabolize nutrients

Protect the intestinal wall

Produce vitamin K and short chain fatty acids (SCFA), which are important for immune health

Maintain health of the digestive tract

Regulate immunity

Prevent inflammation

Promote good brain health and function

As our understanding of healthy gut bacteria evolves, so does the information on how to cultivate your own “microbiome” while inhibiting overgrowth of “bad” bacteria that are infectious and inflammatory. Initially, fermented foods and probiotics were thought to be the main recourse.

Then we learned eating a diet comprised primarily of vegetables and fruits and continually changing up the produce you eat is a great way to develop a rich and diverse gut bacteria population.

Now, scientists have used both a mouse study and a human study to show regular exercise, independent of diet or other factors, also promotes healthy gut bacteria.

In the first study, researchers transplanted fecal material from both exercised and sedentary mice into mice with sterile guts. The activity level of the mice receiving the transplants clearly mirrored that of their donors, showing that the kind of gut bacteria we have plays a role in how inclined we are to be sedentary or active.

The exercised mice recipients also showed more bacteria that produce butyrate, a short-chain fatty acid (SCFA) that promotes healthy intestinal cells, reduces inflammation, and increases energy. They also were more resistant to ulcerative colitis.

In the second study, researchers tracked the composition of gut bacteria in 18 lean and 14 obese adults as they transitioned from a sedentary lifestyle, to an active one, and then back to a sedentary one. Their exercise routine consisted of 30 to 60 minutes of cardiovascular exercise three times a week for six weeks. Their diets remained the same.

They found that exercise raised levels of SCFAs and then declined again as the subjects became sedentary. A rise in SCFAs means concentrations of good gut bacteria increased. The lean participants showed more dramatic increases of SCFAs than obese ones, and more diverse ratios of bacteria, suggesting obese people respond differently to exercise. Nevertheless, increases happened in both populations.

As our knowledge of gut bacteria, functional medicine, and the human body continues to evolve, it nevertheless circles back to some age-old pearls of wisdom: Eat your vegetables and exercise.

You can eat fermented foods every day and take all the probiotic supplements you want, but if you aren’t also feeding those intestinal bacteria what they want, you could be throwing your money away. That’s because to thrive and multiply, healthy gut bacteria need to eat. And what your gut bacteria like best is fiber.

Recently published research done at the University of Oveido in Spain found that obese people with low levels of a group of intestinal bacteria — Bacteroides, Prevotella, and Porphyromonas — also had a lower intake of fruit.

Fruit is a good source of pectin, which is metabolized in the colon by bacteria, such as Bacteroides, producing small chain fatty acids (SCFAs). SCFAs are known to keep the immune system in check and turn down inflammation, known to be implicated in obesity.

The researchers conclude in the journal Nutrients, “These results could be useful for designing strategies targeted to obesity prevention.”

Why Feed Your Microbiome Prebiotics

Researchers have yet to agree on a precise definition of prebiotics, the substances that intestinal bacteria feed on, but generally the scientists agree that these are “undigested dietary carbohydrates that are fermented by colonic bacteria yielding short chain fatty acids.”

Different prebiotics may nourish different types of bacteria, and researchers have not yet pinned down the specifics — that is, exactly what prebiotic nourishes which bacteria. But you can’t go wrong covering your bases by eating with a wide variety of fruits and vegetables.

A high fiber diet has often been recommended for people who need to lose weight, but now we know the point of eating more fiber is not only to make you feel full, but also because of its integral role in sustaining a healthy diversity of gut bacteria. Meanwhile, the opposite — an unhealthy microbiota — is being increasingly associated with inflammation and obesity.

Supporting gut bacteria with probiotics

In addition to a diet of ample and diverse produce that is rich in prebiotic fiber, you can also support your microbiota with probiotics. Probiotics work best when you are already fostering your gut environment with healthy prebiotic fiber. Look for probiotics that will survive the acidic environment of the environment. Many different strains exist and researchers are increasingly finding different strains support different aspects of health. Research which ones may be best for you and switch them up on occasion.

Fermented foods such as kimchee, sauerkraut, kefir, and kombucha contain live microbes that can help improve the health of your gut bacteria. Make sure you get truly live products and not pasteurized. They will usually be in the refrigerated section at the store.

You probably already know the planet is experiencing an extinction crisis; scientists estimate we’ll lose up to 50 percent of current species during the next 20 years. But did you know there’s also an extinction crisis of gut bacteria happening among civilized humans?

The modern diet, which is high in processed foods, meats and sugars but pitifully low in plant fiber appears to have killed off a rich diversity of gut bacteria on which our health depends. The result? Inflammation and chronic disease.

Low fiber kills bacteria and increases inflammation

To prove the point, one study changed the diets of African Americans, who have a high risk of colon cancer, and native Africans in South Africa. They put the African Americans on a native diet high in plant fiber and the native Africans on a typical American diet high in processed foods and meats.

The researchers quickly saw a decrease in colon inflammation in the Americans eating increased fiber, and an increase in colon inflammation in the South Africans on a standard American diet.

In fact, studies of the few remaining indigenous cultures on the planet show humans once served as host to significantly more gut bacteria than is found in Westerners today. These cultures eat about 10 times more plant fiber than the average American. Those bacteria organize themselves in colonies to digest plant fiber, support immunity, and curb inflammation.

People around the world even have different strains of the same bacterium that is native to their area and genetics. Human migration over the years has wiped out some strains, increasing the risk of certain diseases as a result, such as gastric cancer.

How a diversity of gut bacteria protect your health

Just how do bacteria protect us from chronic disease?

For one thing, when they work at breaking down plant fibers, they create compounds called short-chain fatty acids (SCFAs) that stimulate the anti-inflammatory arm of the immune system.

Although it’s possible to supplement with SCFAs, unfortunately they won’t be as beneficial as when your own gut bacteria produce them. This is because the bacteria colonize themselves with similar bacteria in an internal ecosystem that protects the lining of the gut.

Starved bacteria eat the gut lining

One startling revelation researchers found is that gut bacteria starved of the plant fiber they need for fuel instead appear to feed on the protective mucus layer that lines the intestines. Studies of mice fed high-fiber diets showed this mucosal layer was as twice as thick as that of mice on a low-fiber diet.

A too-thin layer of protective mucus allows dangerous bacteria, undigested foods, and other pathogens into the bloodstream, where they trigger system-wide inflammation. This is known as leaky gut.

How to beef up your own gut bacteria

It’s quite possible that many of us today lack the diversity of gut bacteria our ancestors had, and our health suffers as a result. Researchers believe those who grow up on farms, with animals, and exposed to other sources of more diverse bacteria may fare better in terms of microbial diversity.

Nevertheless, a diet high in plant fiber can increase the diversity and population of your gut bacteria, thus helping you balance digestion and tame inflammation. If you find it difficult to tolerate a high-fiber diet, you may have a severe imbalance in your gut bacteria that needs attention. Ask my office for more information.

We’ve all heard that a high-fiber diet is good for health because it keeps the digestive system moving. As it turns out, fiber also plays a more important role than we suspected. To understand why, we need to take a look at the gut microbiome — the community of microorganisms that live in the digestive tract.

Trillions of bacteria live in the human gut –- they account for ten times more cells than in the human body — and they play vital roles in our metabolism and health. It’s a mutually beneficial relationship; the bacteria happily feed on dietary fiber while they perform a variety of duties, including helping to make vitamins B and K, repressing growth of harmful microorganisms, and breaking down and fermenting dietary fiber. This breakdown of fiber results in a release of beneficial, anti-inflammatory short chain fatty acids that are a vital energy source for our bodies.

In recent research, the firmicutes and bacteroidetes classes of gut bacteria have received a lot of attention. Multiple studies show that obese people have a higher concentration of firmicutes than bacteroidetes, while in lean people the bacteroidetes predominate (to help keep it straight, think of fermicutes as “fat” and bacteroidetes as “bony”). Moreover, when the diet is high in fat, the obesity-friendly firmicutes increase (the exception being a ketogenic diet), yet a high-fiber diet helps bacteroidetes increase. In addition, researchers observed that overgrowth of firmicutes led to chronic systemic inflammation, which is known to contribute to common health problems such as metabolic syndrome, diabetes and heart disease. The message: Though they both have jobs to do, you want your bacteroidetes to be stronger than your firmicutes.

Feeding The Magnificent Microbes

One might wish to rid the body of the firmicutes microbes, yet this can actually open the pathway to overgrowth of candida albicans, or a yeast infection, which leads to problems of its own. Instead, supporting a healthy population of bacteroidetes is the key, and this is done by supplying ample prebiotics in the diet. Prebiotics are non-digestible carbohydrates –- in the form of dietary fiber –- that serve as food for the bacteria in your gut.

To keep a healthy balance of bacteria in the gut, an ample supply of fiber-rich plant foods is necessary. These foods should be part of a diet that includes plenty of good fats, vitamins and micronutrients, and avoids bad fats, excess refined sugars, processed/junk foods, and excess alcohol. Good forms of dietary fiber include: All vegetables but especially artichokes, peas, broccoli, and Brussels sprouts; fruits; and beans. Your mother was right, even if she didn’t know the whole truth: Veggies are good for you!

In addition to a diet strong in prebiotic fiber, you can help support a healthy gut environment by using supplemental probiotics: Live, “friendly” bacteria that bolster your gut’s population of healthy microbes. For probiotics to work, there must be a sufficient number of live bacteria present in the product (read your labels!) to survive the acidic environment of the stomach, and reach the large intestine. Your dietary fiber (prebiotics) acts as food to nourish these friendly probiotic bacteria, and ensures their growth and colonization. This combination of pre- and probiotic support can be vital for insuring a healthy gut.

Fermented foods such as sauerkraut, kimchee, kombucha, and yogurt contain live microbes, and can also help boost the probiotic content of your digestive tract. One caution; not all fermented foods have live cultures, and it’s the live ones you want. Again, read your labels!

Medications, hygiene, age, health status, and stress can also influence your gut microbe balance. Eating a fiber-strong, gut-friendly diet and supplementing with probiotics and fermented foods is one of your best strategies for supporting gut health.

We all carry trillions of bacteria in our guts, with as many as a thousand different strains. The composition of these strains, or our “bacterial fingerprint,” can influence whether we are prone to depression, anxiety, or obesity.

Some gut bacteria can make you fat

Studies have shown people (and mice) who are overweight have much higher levels of particular strains of bacteria than thinner subjects. When thin mice are inoculated with bacteria from heavy mice, they gain weight. This is because these fat-promoting bacteria have been shown to encourage overeating, promote weight gain, prevent the burning of fat, and make obese people better at deriving calories from food than thin people.

In a nutshell, your “bacterial fingerprint” plays a role in how much fat you carry and how easy or difficult it is for you to lose weight. Although diet and exercise are important, these findings help to explain why solely relying on the “eat less and exercise more” approach to weight loss is outdated.

Effect of gut bacteria on depression and anxiety

The composition of your gut bacteria can also play a role in whether you suffer from depression and anxiety. For instance, having plenty of beneficial bacteria, such as the Bifidobacteria strain, can promote production of serotonin, the “feel-good” chemical that prevents depression.

On the other hand, too much of “bad” bacterial strains can promote depression and anxiety. This is because the gut is linked to the brain by the vagus nerve, a large nerve that sends messages back and forth between the brain and digestive system. The effects of harmful bacteria in the gut travel to the brain, impacting brain function and mood.

In one study, subjects who took probiotics containing Lactobacillus and Bifidobacterium reported less anxiety, depression, and anger and an improved ability to solve problems. In another study, mice given a Lactobacillus strain cruised through a maze that normally created high anxiety and showed lower levels of the stress hormone cortisol compared to their probiotic-deprived counterparts.

Cultivating good gut bacteria

Although researchers are still unsure exactly how to banish obesity, depression, and anxiety with probiotics, it’s clear you need to enhance your bacterial fingerprint for optimal health.

Birthing and baby feeding affect gut bacteria

The balance of good and bad bacteria starts at birth—vaginal deliveries and breastfeeding have been shown to improve a child’s chances of starting off with a healthy bacterial colony compared to C-sections and bottle feeding.

Chronic stress and gut bacteria

Chronic stress can throw your bacterial harmony out of balance, as can diets filled with sweets and sugars, processed foods, and fast foods. These foods damage and inflame the intestinal walls, promoting overgrowth of bad bacteria and yeasts.

Cultured food and fiber promotes good gut bacteria

You can promote bacterial harmony by focusing on an anti-inflammatory, whole foods diet that includes cultured and fermented foods, such as kefir, sauerkraut, kimchi, and fermented vegetables. If you use store-bought cultured foods, make sure they are the real deal and not simply made with vinegar, or pasteurized, which would kill good bacteria..

A healthy colony of good gut bacteria also relies on plenty of soluble fiber in the diet. Eating plenty of produce will give you just what you need in that respect.

Probiotics for obesity, depression, and anxiety

Fortunately, we have powerful probiotics today that can help you cultivate your inner garden. Probiotics should be stable enough to survive the hot and acidic environment of the stomach and contain ample amounts of beneficial strains. Ask my office for advice on a probiotic that’s right for you.